Breakfast Topic: What do you consider screenshot-worthy?

I have a confession to make: I love screenshots. I take them obsessively. If I'm on an interesting quest, I'll take screenshots of the dialogue. If I find a really cool area in a zone, I'll take a few screenshots of my surroundings. If I'm watching a cut scene, I'll take screenshots of each line of dialogue exchanged. If I learn a new spell with pleasing visual graphics -- you guessed it, screenshot time. I archive my screenshots folders while I'm at it, folders dating all the way back to the beta version of Burning Crusade. Needless to say, screenshots take up a lot of space on my computer. A lot of space.

However, I justify my print-screen obsession by telling myself that any one of those screenshots could be needed for a Know Your Lore article. Or a Breakfast Topic, like this one. Or an opinion piece, or yet another ode to the wonders of transmog. Basically, I'm archiving for a purpose, even if a good three-quarters of those screenshots will never be used. I'm curious, though, because I've noticed people take screenshots for a variety of different reasons -- they like the armor set they just put together, they want to capture something funny that was said in guild chat, they want a record of the scoreboard from their latest arena victory, or maybe they just want a shot of the latest in a long string of progression raid kills. Do you take screenshots? What do you consider screen-shot worthy? What's the oldest screenshot you have in your collection?